Due to the rising cost of diesel fuel and ever-increasing restrictions on exhaust emissions, engine manufacturers have developed engines that utilize alternative fuels. One such fuel is natural gas (NG). While many of these engines consume compressed natural gas (CNG), it may be desirable to transport the NG as liquefied natural gas (LNG) and convert the gas to CNG before it is delivered to the engine. In many cases, the converted CNG must be pressurized before injection into the engine. However, current technology for converting LNG to high pressure CNG requires compressors and/or pumps that necessitate additional power to run, producing unacceptable parasitic losses to engine power (in magnitude and/or quality).
An example of a system for converting liquid fuel to gaseous fuel is disclosed in U.S. Patent Application Publication No. 2010/0005812 by Watts et al (“the '812 publication”). The system of the '812 publication includes a vessel that receives liquid hydrogen from a supply container. The vessel is heated by a heat transfer system to vaporize the hydrogen. The gaseous hydrogen is transferred to au accumulator, where the gas is stored for future use.
While the system of the '812 publication may be capable of converting liquid fuel into a gaseous state, it may be less than ideal. For example, a power source may be necessary to pump the liquid hydrogen from the tank, operate valves that regulate flow of hydrogen through the system, and/or accumulate the gaseous hydrogen. Further, the attained pressure of the gaseous hydrogen may be limited by the dimensions of the vessel, which may be insufficient for certain high-pressure gaseous fuel applications. Also, the attained pressure may be further limited because the pressure in the vessel must be low enough to allow additional hydrogen to enter. This is because the supply pressure must overcome the pressure in the vessel in order for additional hydrogen to enter.
The present disclosure is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.